Offline loading and payload attribute

urbantz/delivery.py

@@ -1,6 +1,7 @@
 from datetime import datetime
 from urbantz.utils import Coordinates
 from urbantz.exceptions import APIError
+import json
 import requests
 
 
@@ -9,15 +10,16 @@ class Delivery(object):
     A UrbanTZ delivery with a unique ID.
     """
 
-    def __init__(self, id):
+    def __init__(self, tracking_code=None):
         """
-        :param str id: A delivery ID.
+        :param tracking_code: A delivery public tracking code.
+        :type tracking_code: str or None
         """
-        self.id = id
+        self.tracking_code = tracking_code
         """
-        The delivery ID.
+        The delivery public tracking code.
 
-        :type: str
+        :type: str or None
         """
 
         self.last_updated = None
@@ -28,6 +30,14 @@ class Delivery(object):
         :type: datetime or None
         """
 
+        self.payload = None
+        """
+        Latest parsed JSON payload from the API. Is None if data has never
+        been fetched from the API or loaded via :meth:`Delivery.use`.
+
+        :type: dict or None
+        """
+
         self.position = None
         """
         Coordinates of the delivery truck's position.
@@ -43,7 +53,7 @@ class Delivery(object):
         """
 
     def __repr__(self):
-        return '{}({})'.format(self.__class__.__name__, self.id)
+        return '{}({})'.format(self.__class__.__name__, repr(self.tracking_code))
 
     @property
     def api_url(self):
@@ -52,7 +62,7 @@ class Delivery(object):
 
         :type: str
         """
-        return 'https://backend.urbantz.com/public/task/tracking/' + self.id
+        return 'https://backend.urbantz.com/public/task/tracking/' + self.tracking_code
 
     def update(self):
         """
@@ -67,10 +77,37 @@ class Delivery(object):
         data = resp.json()
 
         if 'error' in data:
-            raise APIError(data['error'])
+            raise APIError(self.payload['error'])
 
-        self.position = Coordinates.fromJSON(data['position'])
-        self.destination = Coordinates.fromJSON(
-            data['location']['location']['geometry'])
+        self.use(data)
 
+        # TODO: See if the payload holds a last update value
         self.last_updated = datetime.now()
+
+    def use(self, payload):
+        """
+        Use a parsed JSON payload to update the properties.
+
+        :param dict payload: A parsed JSON payload from the API.
+        """
+        self.payload = payload
+        self.position = Coordinates.fromJSON(self.payload['position'])
+        self.destination = Coordinates.fromJSON(
+            self.payload['location']['location']['geometry'])
+
+    @classmethod
+    def from_payload(cls, payload):
+        """
+        Create a Delivery instance from an existing payload.
+
+        :param payload: A parsed JSON payload, a str holding a JSON payload,
+           or an open file-like object.
+        :type payload: dict or str or file-like object
+        """
+        if isinstance(payload, str):
+            payload = json.loads(payload)
+        if not isinstance(payload, dict):
+            payload = json.load(payload)
+        instance = cls()
+        instance.use(payload)
+        return instance